When casting news for the film adaptation of E.L. James' erotic romance novel "Fifty Shades of Grey" broke over the long weekend, reactions were muddled with expressions running from "Finally!" to "Seriously?!"

Producers Dana Brunetti and Michael De Luca also felt the need to clarify why they made their choices

"There is a lot that goes into casting that isn't just looks. Talent, availability, their desire to do it, chemistry with other actor, etc.," wrote Brunetti, adding, "So if your favorite wasn't cast, then it is most likely due to something on that list. Keep that in mind while hating and keep perspective."

Each of them also had to audition for his or her role and reportedly had to do a "chemistry read," which probably meant they had to do a scene on video together so that producers and Universal Pictures execs could see that they had enough "heat" for the film, the Wrap said.

Several young actresses reportedly passed on the role because of the frontal nudity required. ("Like Crazy's" Felicity Jones reportedly dropped out because of it.) "Divergent's" Shailene Woodley, Alicia Vikander, Imogen Poots and Elizabeth Olsen were also considered for the role, and "Harry Potter's" Emma Watson in March put the kibosh on rumors that she would participate in the film.

For a while, it was believed "White Collar's" Matt Bomer or "The Vampire Diaries'" Ian Somerhalder were front-runners for Christian. (Somerhalder would have been an interesting choice because James' series started off as "Twilight" fan fiction and many see parallel adult arcs to Stephenie Meyer's bestselling young-adult books.)

Hunnam wasn't really the front-runner for the career-defining role, either, according to author and screenwriter Bret Easton Ellis, who said another British actor, "Twilight" heartthrob Robert Pattinson, was James' first choice. Yep, we're definitely seeing that "Twilight" parallel now.

"Talked to E.L. James at a party over the summer: her first choice for Christian was Rob Pattinson," he tweeted. "She and I were at Rob Pattinson's house when she admitted that Rob was first choice for Christian. When E.L. James asked me who I thought should be Christian I said 'James Deen, of course,' and then she shoved me."

Since the announcement, a petition on Change.org surfaced asking that the film be recast with Bomer and "Mad Men's" Alexis Bledel in the lead roles. (Fan posters featuring their faces have even cropped up.)

Hunnam, who starred in Guillermo Del Toro's "Pacific Rim" this summer, at least has people rooting for him.

"First of all, I think he's going to do fantastic because he's a great actor and a handsome guy," his "Pacific Rim" costar Charlie Daytold E! "And when you're seeing a movie about sex, you want a handsome guy. On top of that, he's a good actor, so I think he's going to do a great job."

And "Sons of Anarchy" creator Kurt Sutter is convinced Hunnam will do well.

"haven't read the books, all i know is that charlie will bring gravitas," Sutter said during a Twitter Q&A.

Sam Taylor-Johnson will direct the film based on screenwriter Kelly Marcel's script. James reportedly had a significant say in casting, and production is supposed to begin this fall so that the film can hit theaters in August, the Wrap said.

So who would your choices be for Christian and Ana? And how do you feel about the film's casting as it stands?